Irritable bowel syndrome (IBS) is a common chronic disorder of the intestine that affects 20 to 60 million individuals in the US alone (Lehman Brothers, Global Healthcare-Irritable Bowel Syndrome Industry Update, September 1999). IBS is the most common disorder diagnosed by gastroenterologists (28% of patients examined) and accounts for 12% of visits to primary care physicians (Camilleri 2001 Gastroenterology 120:652-668).
Diabetes mellitus (DM) is a group of metabolic diseases characterized by hyperglycemia, resulting from defects in insulin secretion, insulin action, or both. The chronic hyperglycemia of diabetes is associated with long-term damage, dysfunction, and failure of various organs, especially the eyes, kidneys, nerves, heart, and blood vessels. Well-known risk factors of type 2 DM are family history, obesity, age, race, prediabetes [impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT)], gestational DM, and polycystic ovarian syndrome. An association between insulin resistance and inflammation has been reported. Data also indicated a correlation that prediabetes was common in patients with IBS, which suggested that the chronic inflammation process might be responsible for the progression to DM.
Hypercholesterolemia has been recognized as a major risk factor for coronary heart disease (CHD). In clinical trials, reducing serum LDL cholesterol has been demonstrated to decrease the incidence of CHD and to reverse atherosclerotic lesions. Two main classes of clinically useful hypocholesterolemic agents are the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (e.g., statins) and the bile acid sequestrants. Both induce hepatic LDL receptor activity by increasing hepatic cholesterol demand. Because the major determinant of serum cholesterol level is hepatic LDL receptor activity (38), these agents may share a common mechanism leading to reduction in serum cholesterol.
The guanylate cyclase-C (GC-C) receptor (reviewed by Lucas et al. 2000 Pharmacol. Rev 52:375-414 and Vaandrager et al. 2002 Molecular and Cellular Biochemistry 230:73-83) is a key regulator in mammals of intestinal function (although low levels of GC-C have been detected in other tissues). GC-C responds to the endogenous hormones, guanylin and uroguanylin, and to enteric bacterial polypeptides from the heat stable enterotoxin family (ST polypeptides). When an agonist binds to GC-C, there is an elevation of the second messenger, cyclic GMP, and an increase in chloride and bicarbonate secretion, resulting in an increase in intestinal fluid secretion.
Given the prevalence of diseases associated with GI inflammation, hypercholesterolemia, obesity and inflammatory conditions, there exists a need to develop compositions and methods for effective treatment.